Given two standalone Splunk environments, can I point one instance to search the other instance in addition to its own instance?

I am working with two Splunk standalone environments where each environment is a single server that acts as search head and indexer. Users currently have to log into both environments to run reports. They want to only log into one server and run a combined report. I understand that the optimal solution is to have one environment but this is not currently possible. Can I update the distributed search settings in System A to search both itself and also System B? Looking at the docs for distributed search I see this line: **Important**: A search head cannot perform a dual function as a search peer.